反应详情

温度

0 °C

β-Glucanase is preferably incorporated in the composition in such quantities that the composition has a glucanolytic activity in the range of from 0.05 U/g to 1.00 U/g and more preferably in the range from 0.06 U/g to 0.25 U/g. The determination of glucanolytic activity is based on modifications of the process described by M. Lever in Anal. Biochem. 47 (1972), 273-279 and Anal Biochem. 81 (1977), 21-27. A 0.5% by weight solution of β-glucan (Sigma No. G6513) in 50 mM glycine buffer (pH 9.0) is used for this purpose. 250 μl of this solution are added to 250 μl of a solution containing the agent to be tested for glucanolytic activity and incubated for 30 minutes at 40° C. 1.5 ml of a 1% by weight solution of p-hydroxybenzoic acid hydrazide (PAHBAH) in 0.5M NaOH, which contains 1 mM bismuth nitrate and 1 mM potassium sodium tartrate, are then added, after which the solution is heated for 10 minutes to 70° C. After cooling (2 minutes/0° C.), the absorption at 410 nm is determined against a blank value at room temperature (for example with a Uvikon® 930 photometer) using a glucose calibration curve. The blank value is a solution which is prepared in the same way as the measuring solution except that the glucan solution is added after the PAHBAH solution. 1.00 U corresponds to the quantity of enzyme which produces 1 μmole of glucose per minute under these conditions.

1. additioncontaining the agent
2. additionare then added
3. temperatureafter which the solution is heated for 10 minutes to 70° C
4. customthe absorption at 410 nm
5. customis determined against a blank value at room temperature
6. customis prepared in the same way as the measuring solution except that the glucan solution
7. additionis added after the PAHBAH solution